A great challenge for the development of advanced polymeric materials is how to precisely design molecular architectures that could integrate superior material properties, such as high mechanical strength and toughness, good solvent and heat resistance, self-repairing ability and eco-friendliness, into one structure. Inspired by the hierarchical structures in spider silk, the self-healing phenomenon in biological system and the delicately controlled cross-linking in bioelastomers, we report a novel molecular design and synthesis of high-performance and thermally recyclable cross-linked polymers. In these materials, the reversible covalent cross-links among H-bonding hard segments are incorporated into linear segmented polyurethane via Diels-Alder reaction between maleimide pendant groups of the chain extender and furan cross-linker containing urethane bonds, and the microscopic hierarchical structure comes from the microphase separation of mobile and rigid segments as well as the densely H-bonding assemblies. Our synthesized polymers not only exhibit excellent comprehensive mechanical properties, including high stiffness, strength, and toughness, but also have good solvent and heat resistance, and can be well reshaped and re-mended at an elevated temperature, making them eco-friendly and have great potential for widely industrial applications. Our bio-inspired molecular design concept of high-performance and recyclable cross-linked polymers provides a new insight into the development of advanced polymer materials.
Advanced Materials 2013, 25 , 4912-4917
http://onlinelibrary.wiley.com/doi/10.1002/adma.201301513/abstract;jsessionid=5C272BD72914946E2328207269162097.d04t01